1. Field of the Invention
This invention relates to detergent compositions in the form of tablets for use in fabric washing, and, more particularly, to a composite disintegration blend of defined amounts of a water-soluble salt, a cellulosic material and crosslinked polyvinylpyrrolidone, having a disintegration rate of at least 100 g/min.
2. Description of the Prior Art
Such tablets have the advantage that they do not require the user to measure out a volume of powder or liquid. Instead one or several tablets provide an appropriate quantity of composition for washing a single load in a washing machine or possibly by hand. They are thus easier for the consumer to handle and dispense.
Detergent compositions in tablet form have been described in a number of documents and are sold commercially.
Such tablets generally are made by compressing or compacting a quantity of detergent composition in particulate form. It is desirable that tablets should have adequate mechanical strength when dry before use, yet disintegrate and disperse/dissolve quickly when added to wash water. There is difficulty in achieving both properties simultaneously. As more pressure is used when a tablet is compacted, so the tablet density and strength rise, but there is also a reduction in the speed of disintegration/dissolution when the tablet comes into contact with wash water at the time of use. Organic detergent serves as a binder, but a typical quantity of such detergent can also retard disintegration and dissolution of a tablet.
The prior art has described the numerous difficulties in providing suitable tablets of detergent compositions, including EPA 466485; WO 00/32741; EPA 711827; EPA 838519; WO 99/36493; WO 98/55583; GB 911204; U.S. Pat. No. 3,953,350; JP 60-015500A; EP-A-711827; WO 96/28530; EP 1070741; and EP 1036839.